A Complex Process, Stated Simply

The actual carving of Crazy Horse Mountain continues with a perfect, and necessary, blend of skill and knowledge in engineering, geology, and art. These abilities are contained within a select group of dedicated Mountain Crew Members who are willing to work hard. The members of the Crazy Horse Mountain Crew are experts in equipment operation, engineering, and precision blasting. Safety is the Crew’s top priority.

The carving process is deeply complex. With the Mountain as the centerpiece of the Crazy Horse Mission, and an exposed work-of-art in progress, it is a perpetual conversation piece. Sharing pertinent facts for such conversations is truly important to us at the Memorial.

Simplified, and viewing the picture fully “zoomed-out”, Sculptor Korczak Ziolkowski’s scale model, increased exponentially, is being carved in granite to honor all North American Indians. The finished sculpture of Lakota Warrior Crazy Horse upon his Steed will be 563’ high and 641’ long.

When zoomed in to view more detail, the process gains complexity.

Measure, Survey, Repeat

A vital step in telling this story in stone is ensuring Sculptor Korczak’s masterpiece fits within’ its granite boundaries. Korczak himself relied on artistic estimates and his incredibly trained eye and natural feel for dimensions and scale. He used a combination of his artistic visual ability, tape measures, and a beautiful old theodolite (survey instrument) to determine the basic location of his model within the Mountain and to begin the process of removing excess rock.

In the late 1980s, after Korczak had passed away and the progressing Sculpture was under the direction of his wife Ruth, a 48-foot long measuring boom was fixed to the top of Crazy Horse's Head to accomplish carving Crazy Horse’s Face. Daughter of Korczak and Ruth, and current Mountain Carving Director, Monique Ziolkowski, spent countless hours gathering exact measurements using the pointing system on her Dad’s 1/34th scale model of Crazy Horse's Face. A plumb bob suspended from the measuring boom was then used to transfer numbers to the Mountain.

Existing systems for measuring have evolved steadily throughout the course of history, yet, this step has remained basically the same since the beginning; measure the scale models and transfer the measurements, multiplied exponentially, to the Mountain. Now, measurements are gathered from several working scale models, ranging from 1/34th to 1/300th, which have evolved with gained knowledge of the Mountain’s geology.

The Crew relies on laser scanners that provide a three-dimensional computer model of the planned sculpture from working scale models. Laser scanning equipment has been used to measure the entire Mountain on several occasions. This technique allows for measuring many points quickly and accurately and then to build 'digital models' of the Mountain in engineering computers, which allow us to see Korczak’s model inside the Mountain.

On the Mountain, a survey control system was developed after Crazy Horse’s Face was completed. This instrument, known as a Total Station, measures very precise angles and distances from known control points to calculate three-dimensional coordinates for any point on the Mountain. It uses an infrared beam reflected from a hand-held prism to measure distances up to several thousand feet with accuracy to the nearest 1/1000th of a foot.

Collectively, these techniques and tools provide measurements and coordinates for the Carvers to guide them in removing the rock that covers the Sculpture.

So how do they remove the rock?

Drilling

Equipment has evolved from Korczak's use of a single-jack (sledge hammer and steel) to drill the holes for the first blast on the Mountain. With the current focus being very near finish grade, the Carvers take away most rock by hand and with very little blasting. The Mountain Crew uses hydraulic drills, some mounted on large pieces of equipment, as well as hand drills.

Feathers and Wedging and Taking Rock Away

Using pre-drilled holes, Crew Members pound in feathers and wedge sets, which allow them to break the rock free from the Carving. In addition, they have recently acquired rock splitters, which do the same thing as a feathers and wedge set with less effort required physically.

After rock has been severed from the Mountain, the majority is hauled away by a variety of methods. The Manitou 3255RT is extremely useful in carrying away both large boulders with straps attached or a load of smaller fragments in the three-sided custom welded box. On Crazy Horse’s Head, the Potain IGO T130 self-erecting Crane is responsible for lowering most fragments to the ground. After granite pieces are on the main ground level from any of the current work areas, they are hauled away by a pick-up with a dump box.

Blasting

With present-day work areas so near to finish grade, very little blasting is used currently. When it is, all blasts at Crazy Horse are designed, drilled, and executed to protect the rock that is left after the blast. This is the opposite of most blasting operations, where the main concern is the final size and location of the material being blasted away. The mountain crew prepares most blasts using a system that explosive engineers call "pre-splitting." This is similar to perforating a piece of paper to allow it to tear evenly. The rock to be removed is drilled on all sides with a series of parallel drill holes. Explosives are detonated throughout the entire length of each of the drill holes, cleanly removing the desired rock while leaving the remaining rock undamaged.

Finishing

Finishing work is accomplished as it was on Crazy Horse's Face. A jet torch running on diesel fuel and compressed air (operating at 3,300 degrees (F)) is used in a process is called spalling. Spalling removes drill marks and makes the surface smooth. The tip of Crazy Horse’s Left Index finger was smoothed by torch in late 2017. The Carvers have found the recently acquired remote controlled Brokk 110 an extremely useful addition to hold the torch safely and steadily.

The final finishing step, and repeated maintenance task, is to seal the natural seams in the granite to minimize the naturally occurring effects of freeze/thaw cycles.

Work in Many Areas

The Mountain Crew is steadily removing rock from several areas simultaneously. With the Carvers split into smaller groups, safely and deliberately speckled across the Sculpture in progress, it is quite a sight that has only been imagined to this day. It is important to remember, even on the World's Largest Mountain Carving, space is limited. This strategic placement of Carvers is a necessity as their safety and the integrity of the Monument relies heavily upon respecting the allowable capacities (laborers and equipment) for each space.

The Mountain Crew is currently removing rock on Crazy Horse’s Left Hand, which will be about 25 feet tall. The extended Left Index Finger, resting on the supporting Horse’s Mane will be nearly 29 ½ feet long.

Other areas of the sculpture taking shape are Crazy Horse’s Left Arm, his Left Knuckle area, the top of his Head and Hairline, and the Horse’s Mane.

For weekly facts about the work on the Mountain, check out our #MountainMonday posts on Facebook.